The purpose of this study was to assess the influence of age, training status and muscle fibre type distribution on cycling efficiency. Forty males were recruited into one of 4 groups: young and old trained cyclists, young and old untrained individuals. All participants completed an incremental ramp test to measure their VO2peak, maximal heart rate (HRmax) and maximal minute power output (MMP); a submaximal test of ratio corrected cycling gross efficiency at a series of absolute and relative work rates; and in trained participants only, a 1-hour cycling time trial. Finally, all participants underwent a muscle biopsy of their right vastus lateralis muscle. At relative work rates, a general linear model found significant main effects of age and training status on cycling efficiency (P<0.01). The percentage type I muscle fibres was higher in the trained groups (P<0.01), with no difference between age groups. There was no relationship between fibre type and cycling efficiency at any work rate or cadence combination. Stepwise multiple regression indicated that muscle fibre type did not influence cycling performance (P>0.05). Power output in the 1-h performance trial was predicted by average VO2 and GE, with standardised beta coefficients of 0.94 and 0.34 respectively, although some mathematical coupling is evident. These data demonstrate that muscle fibre type does not affect cycling efficiency and was not influenced by the ageing process. Cycling efficiency and the percentage of type I muscle fibres were influenced by training status, but only GE at 120 rev⋅min-1 was seen to predict cycling performance.
- Gross Efficiency
- muscle fibre type
- maximal oxygen uptake
- endurance performance
- Copyright © 2013, Journal of Applied Physiology